Стан соснових насаджень на водно-льодовикових відкладах у Житомирському поліссі

The results of researches of the state of forest plantations of pine trees of different ages on water-glacial deposits in Zhytomyr Polissya are presented. The phyto-indicative analysis describes the types of forest conditions, such as: fresh bory and fresh subory. It is established that about 40 % of trees grow in fresh bory by the first class of Kraft and in fresh subory – about 50 %. The first class of merchantability includes 30 % of trees in fresh bory and 47 % of trees from their total number in fresh subory. The number of weakened, dying and dead trees in fresh bory is 35.5 %, and in fresh subory 54.3 %. The dying and dead trees appear as a result of diseases, insect pests and competition for nutrients. It is found out that the absolute value of the annual tree rings decreases with the increase in the age of pine: in fresh bory by 28.0 %, in fresh subory by 50.5 %. It is established that the least annual rings are characteristic for plantations of fresh bory, and the widest ones – for tree stands growing in richer conditions (fresh subory). The maximum values of the growth of annual rings are recorded for mature and overmature forest stands, regardless of forest conditions. By dendrochronological analysis it is established that the annual radial increment of the pine varies between 1.19–3.94 mm. By the values of the standard deviation it is clear that the organization of the system continues in the fresh bory throughout the studied period, and in the fresh subory – the system is formed at the age of up to 40 years. By the values of the coefficients of variation, the structural stability of plantations on water-glacial deposits decreases with age. It is established that identical or similar coefficients of variation are recorded in all age groups. Thus, all this time the proportion of anomalous components of radial growth increases, the plantations are structurally unstable and more vulnerable to environmental factors. According to that it can be asserted that in fresh bory, in fact, stable, internally balanced Scots pine stands are not formed in practice, while in fresh subory pine stands are organized in a single phytosystem only after 60 years.